The present invention pertains to a key-operated calculator, and more particularly to a key-operated program calculator capable of performing a specific program calculation in response to sequentially entered plural kinds of input data items.
Most of key-operated calculators, for example, calculators storing a plurality of kinds of fixed programs and programmable calculators, needs a plurality of kinds of input data items rather than a single kind of input data item to perform a specific program calculation (that is, complicated calculations except for four rule operations).
In this case, the orders of entering the input data items are previously determined in advance in accordance with desired program calculations and therefore the operator must learn in advance the respective orders of manual operations of keys. This means that the operator shall introduce desired input data items into calculators while keeping in mind the orders of manual operations of keys. Such a requirement is very troublesome to the operator and may cause operator's errors in the entry of input data.
Therefore, it is an object of the present invention to provide an improved display means effective to key-operated calculators which performs a specific program calculation in response to sequentially applied input data items. According to the improved display means of the present invention, certain kinds of input data items to be entered are visually displayed in the form of its abbreviations, thereby visually indicating to the operator the kinds of input data items which must be next introduced.
By way of example, in electronic calculators containing a plurality of kinds of fixed programs, the present invention is practiced in the following manner.
1. While performing a fixed program calculation, the specific kinds of input data items which must be next introduced are visually displayed in the form of abbreviations through the utilization of a specific digit element of a multi-digit segment type display.
2. Kinds of input data items being currently introduced are visually displayed in the form of abbreviations through the utilization of a specific digit element of a multi-digit segment type display.
3. Kinds of calculation results are visually displayed in the form of its abbreviations by utilization of a specific digit element of a multi-digit segment type display.